Pneumatic rotary drill hammer



March 26, 1957 R. o. DULANEY PNEUMATIC ROTARY DRILL HAMMER 2Sheets-Sheet 1 Filed Feb. 24, 1956 FIG. .1.

INVENTOR. P/CHAQD O. 004 A/VEY,

2 Sheets-Sheet 2 FIG. 6.

R. O. DULAN EY PNEUMATIC ROTARY DRILL HAMMER xmx P/ March 26, 1957'Filed Feb. 24, 1956 I N V EN TOR.

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PNEUMATIC RUTARY DRILL HAMMER Richard 0. Dulaney, Fort Worth, Tex.

Application February 24, 1956, Serial No. 567,614

3 Claims. (Cl. 121-30) This invention relates to well drillingequipment, and more particularly to an air hammer for a well drillingapparatus.

The main object of the invention is to provide a novel and improved airhammer device operated by compressed air, or similar fluid underpressure, and being particularly arranged to cooperate with the bit of arotary well drilling tool, the improved air hammer being simple inconstruction, being easy to install on a well drilling pipe, and beingprovided with means for receiving and supporting a well drilling bittherebeneath.

A further object of the invention is to provide an improved air hammerfor a well drilling apparatus, said air hammer involving relativelyinexpensive components, being rugged in construction, being reliable inoperation, and being easy to maintain in working condition.

Further objects and advantages of the invention will become apparentfrom the following description and claims, and from the accompanyingdrawings, wherein:

Figure 1 is a vertical cross-sectional view taken axially through thelower portion of a well drilling pipe provided with an air hammerconstructed in accordance with the present invention;

Figure 2 is a horizontal cross-sectional view taken on the line 22 ofFigure 1;

Figure 3 is a horizontal cross-sectional view taken on the line 3-3 ofFigure 1;

Figure 4 is a horizontal cross-sectional view taken on the line 4-4 ofFigure 1;

Figure 5 is a vertical cross-sectional view, similar to Figure 1, butshowing the piston element of the air hammer in a partly elevatedposition prior to reaching the top end of its stroke; and

Figure 6 is a vertical crosssectional view of the air hammer, similar toFigure 1, but showing the piston element substantially at the top end ofits stroke with the air release valve opened and with the piston elementabout to be forced down to deliver its impact to the bottom fitting ofthe hammer.

Referring to the drawings, 11 designates the lower end of a section ofwell drilling pipe, said lower end being provided with the internallythreaded conical bore 12 adapted to receive the externally threaded topend 13 of a rotary drilling tool 14. Designated generally at is an airhammer, according to the present invention, which is interposed betweenthe drill pipe section 11 and the drilling tool 14 in a manner presentlyto be described.

The air hammer 15 comprises an annular top fitting 16 having anexternally threaded conical tip 17 which is threadedly engageable in theconical bore 12 in the manner shown in Figure 1, whereby the top fitting16 may be secured to the drill pipe section 11 in place of theconventional drilling tool 14. As shown, the top fitting 16 has the bore18 which communicates with the bore 19 of the drill pipe section 11.Designated at 21) is a cylinder which is threadedly engaged on thedepending lower portion 21 of the annular top fitting 16, and slidablypositioned in the cylinder is a relatively massive piston 22,

atent 2 said piston being provided with a plurality of sealing rings 23whereby the piston sealingly and slidably engages the inside surface ofthe cylinder 20.

Designated at 24 is a tubular piston rod which is threadedly engaged inthe center portion of the top piston 22 and which is slidably receivedat its upper portion in the bore 18 of top fitting 16. A coiled spring25 surrounds the tubular piston rod 24 and bears between the top surfaceof piston 22 and the bottom surface of the annular fitting 16 to exert adownward force on the piston 22.

The piston 22 is formed with a pair of downwardly divergent passages 26,26, said passages communicating at their top ends with the tubular rod24 and communicating at their bottom ends with the space below thepiston 22. Designated at 27 is an annular bottom fitting which has areduced upper portion 28 threadedly engaged in the bottom end ofcylinder 20 and which is formed with a vertical upstanding sleeveportion 29 whose top edge is engageable by the piston 22 to limit thedownward move ment of said piston in the cylinder 20.

The bottom fitting 27 is formed with the axial, internally threadedconical bore 30 adapted to threadedly receive the externally threadedconical top end portion 13 of the drilling tool 14 in the mannerillustrated in Figures 1, 5 and 6.

The bottom fitting 27 is formed with the threadedly cylindrical topcavity 31 located axially in the fitting and communicating with theoutlet bore 32 of the fitting. The bore 32 communicates with the centralbore 33 of the tool 14. The upstanding sleeve portion 29 of the bottomfitting 27 defines a cavity 34 having an annular bottom wall portion 35surrounding the cylindrical recess 31 and defining a valve seatengageable by an annular valve element 36 mounted on a short cylindricalsleeve member 37. The sleeve member 37 is slidably engaged on adepending tubular bottom rod 38 threadedly secured in the centralportion of the bottom of piston member 22 and being in axial alignmentwith said piston. A coiled spring 37 surrounds the depending bottom rod38, the lower end of the coiled spring being secured to the annularvalve element 36 and the top end of said coiled spring being secured tothe bottom surface of the piston 22, whereby the tubular member 38 maybe forced at times into the recess 31 and may move downwardly relativeto the annular valve element 36 which is thus held sealingly against thevalve seat 35 by the coiled spring 37. At other times, as for example,when the piston member 22 is elevated in the cylinder 20, as shown inFigure 6, the spring 37 lifts the valve element 36 off the valve seat35.

The lower end of the depending tubular rod 38 is formed with an annular,outwardly projecting stop flange 4t) limiting downward movement of thesleeve rnemb 37 with respect to the tubular rod 33.

The piston member 22 is formed with a pair of upwardly divergent airpassages 41, 41 which communicate at their lower ends with'the interiorof the depending tubular rod 33 and which communicate at their upperends with the space 43 between the piston member 22 and the top fitting21.

In operation of the hammer, compressed air, or similar fluid, is forceddownwardly from bore 19 into bore 18 and through the depending pistonrod 24 into passages 26, 26, and thus into the space 34, with the pistonmember 22 in its lowered position, shown in Figure 1. The tluid buildsup pressure in the space 34, causing the piston member 22 to be elevatedagainst the force of the top spring 25 and against the tension of thelower spring 37. until the upward movement of the piston member 22 hasdeveloped sufiicient tension in the lower spring 37 to raise the annularvalve element 36 oi? the valve seat 35. Figure 5 illustrates theposition of the piston member 22 immediately prior to this condition.

As soon as the valve element 36 is lifted off the valve seat 35, thecompressed fluid in the space 34 discharges through recess 31 and bore32 into the bore 33 of the tool and at the same time flows upwardlythrough the depending bottom tube 38 and passages 41, 41 into the space43. The sudden reduction of pressure in space 34, combined with theapplication of fluid pressure to the top vof the piston member 22 by thefluid rapidly discharging into the space 43 develops a substantialdown-ward force on the piston 22, which is combined with the forcedeveloped in the compressed upper spring 25, causing the piston member22 to travel downwardly and to strike the top edge of the upstandingsleeve element 29 with considerable force.

This heavy impact is transmitted directly to the tool 14 by the bottomfitting 27. As the piston member 22 moves downwardly to deliver theaforesaid impact to the drilling tool, the annular valve element 36engages the annular sleeve 35, sealing o'tf space '34 from recess 31,and allowing compressed air entering the space 34 from the passages 26,26 to again build up pressure in said space 34. This commences the nextcycle of operation, similar to that above described, whereby repeatedimpacts are delivered to the drilling tool 14 responsive to the supplyor compressed air to the hammer device through the drill pipe bore 19.

While a specific embodiment of an improved air hammer device for a welldrilling apparatus has been disclosed in the foregoing description, itwill be understood that various modifications within the spirit of theinvention may occur to those sklled in the art. Therefore, it isintended that no limitations be placed on the invention except asdefined by the scope of the appended claims.

What is claimed is:

1. In an air hammer for a well drilling apparatus, an annular topfitting adapted to be secured in the lower end of a drill pipe, acylinder secured axially to said top fitting, an annular bottom fittingsecured axially to the lower end of said cylinder, a hammer pistonslidably mounted in said cylinder, a tubular piston rod connected to thetop end of said piston and slidably engaged in said top fitting, springmeans acting between said piston and top fitting, biasing the pistondownwardly, a tubular bottom rod secured to the bottom end of saidpiston, an annular valve element slidably mounted on said bottom rod andbeing sealingly engageable on said bottom fitting, and spring meansconnecting said valve element to said piston, said piston being formedwith a first air passage connecting said tubular top red to the spacebetween the piston and the bottom fitting and with a second air passageconnecting said tubular bottom rod to the space between the piston andsaid top fitting, whereby air under pressure entering said first namedspace builds up pressure to elevate the piston and to lift the valveelement ofi the bottom fitting, allowing the piston to descend withhammer force on said bottom fitting because of the combined effects ofthe transmission of the compressed air to said second named space andthe first named spring means.

f2. In an air hammer fora welldiilling'apparatus, an annular top fittingadapted to be secured in the lowerend of a drill pipe, a cylindersecured axially to said top fitting, an annular bottom fitting securedaxially to the lower end of said cylinder, a hammer piston slidablymounted in said cylinder, a tubular piston rod connected to the top endof said piston and slidably engaged in said top fitting, a first coiledspring surrounding said piston rod and acting between said piston andtop fitting, biasing the piston downwardly, a tubular bottom rod securedto the bottom end of said piston, an annular valve element slidablymounted on said bottom rod and being sealingly engageable on said bottomfitting, a second coiled spring connecting said valve element to saidpiston, said piston being formed with a first air passage connectingsaid tubular top rod to the space between the piston and the bottomfitting and with a second air passage connecting said tubular bottom rodto the space between the piston and said top fitting, whereby air underpressure entering said first named space builds up pressure to elevatethe piston and to lift the valve element off the bottom fitting,allowing the piston to descend with hammer force on said bottom fittingbecause of the combined effects of the transmission of the compressedair to said second named space and the first named coiled spring.

3. In an air hammer for a well drilling apparatus, an annular topfitting adapted to be secured in the lower end of a drill pipe, acylinder secured axially to said top fitting, an annular bottom fittingsecured axially to the lower end of said cylinder, a hammer pistonslidably mounted in said cylinder, a tubular piston rod connected to thetop end of said piston and slidably engaged in said top fitting, a firstcoiled spring surrounding said piston rod and acting between said pistonand top fitting, biasing the piston downwardly, a tubular bottom rodsecured to the bottom end of said piston, said bottom fitting beingformed with an axial recess formed and arranged to at times receive thelower portion of said tubular bottom rod and with an annular valve seatin its top end around said recess, an annular valve element slidablymounted on said bottom rod and being sealingly engageable on saidannular valve seat, a second coiled spring surrounding said bottom rodand connecting said valve element to said piston, said piston beingformed with a first air passage connecting said tubular top rod to thespace between the piston and the bottom fitting and with a second airpassage connecting said tubularbottom rod to the spacebetween the pistonand said top fitting, whereby air under pressure entering said firstnamed space builds up pressure to elevate the piston and to lift thevalve element oil? the bottom fitting, allowing the piston to descendwith-hammer force on said bottom fitting because of the combinedefifects of the transmission of the compressed air to said second namedspace and the first named coiled spring.

References Cited in the file of this patent UNITED STATES PATENTS1,264,318 McGrath Apr. 30, 1918 1,665,046 Tucker Apr. 3, 1928 1,828,604Humphreys Oct. '20, 1931 2,403,582 Caudill July 9, 1946

